HERE IT IS: Marissa Mayer's New Yahoo.com Homepage

Marissa Mayer made her fame and fortune at Google, where she was responsible for the original design of Google.com.

And now, two months after becoming Yahoo CEO, she has updated Yahoo.com.

A new version is slowly being rolled out into the wild, and we've got a screengrab that a source close to Yahoo tells us is authentic.

Yahoo.com is Yahoo's most important product. ComScore says 170 million people visit Yahoo sites everyday, and a huge percentage of them are funneled to this page. Its ad units are perhaps the most valuable on the Internet.

Sources tell us more changes are on the way. The page is going to get more personalized and customizable, we hear.

Here are today's big changes to the page:

The search bar is now centered, and is part of a darker toolbar that is fixed to the top of the page as the user scrolls down.